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goodelsha
05-01-2010, 05:37 PM
I just picked up a 2000 Prostar 205V with 160 hours at the end of last year...I was only able to take it out twice before storing for the winter, and boat ran great.

I de-winterized and took the boat out, and it had a hard time keeping from stalling, even died twice on me. RPM's were fluctuating between 500 and 1000. Boat ran great above idle, but each time I would bring it back to neutral, it would almost stall, rev up, down, up down, etc...

Maintenance done:

Impeller
Plugs
PCV valve
Cleaned Spark arrestor
Pulled Idle Air Sensor and cleaned
Oil change
Transmission Oil Change
I added Stabil to a full tank at the end of last year.

This is my first MC and I've been learning a ton on this forum. Any ideas what would be causing this?

agua4fun
05-01-2010, 07:52 PM
When my alternator was dying, my boat did that. (01 PS190 With LTR)
I'm no mechanincal/electrical pro, but thats my suggestion FWIW

MariStar-Man
05-01-2010, 09:13 PM
plugs are gapped correctly?

not insulting your cred' just askin...

make sure all the spark plug wires are tight.

I have the LTR 330hp. Is yours 330 hp as well?

I'm not the best mechanic, but I hope someone knows about this...

Maybe try some fresh gas?
some stabil people i think said they had similar problem

Good luck

Jorski
05-01-2010, 09:20 PM
dirty fuel filter ?

russlars
05-01-2010, 10:08 PM
Mine hasn't done this, but my friends always does this on the first tank of gas he runs through it after winter storage. He says that it is the fuel stabilizer. After the first tank the idle problem goes away.

goodelsha
05-02-2010, 12:15 PM
Voltmeter reads 12.5v at the battery w/ engine off, and jumps up to 13.9v with the boat at 1,000rmps.

Pulled the plugs and made sure they are gapped at .045 per service manual. I did notice some water drops on the plugs?? Maybe condensation?

Not sure if the PO ever changed the fuel filter, so I'm going to order a new one, and try some fresh gas....I have the filter located in the tank, lucky me.

goodelsha
05-14-2010, 07:54 PM
This week I replaced the fuel filter, syphoned the gas out, and pumpped in 28 gal of 91. I took it to the lake for a test run, and it did not idle very well. It would stumble and stall....the only way I could keep it going was to rev up to 1,000 RPMs, once warm, no problem. Cruised around the lake, shut down, and it fired and idled fine. I figured any bad gas would have been burnt off by now.

Today, dropped her in the water, same thing. Stumble and stall until warm. What else can I check?

coz
05-14-2010, 08:09 PM
Those sound like the symptons of a bad IAC (Idle Air Control) and it's a $120 item from NAPA.

seth25
05-17-2010, 09:47 AM
I'm having the same problem. Boat runs flawless when warm. I was trying to teach my wife wakeboarding yesterday. I could go neutral, drive, neutral, drive, no problem, no surging. If I had the boat off for a while then started it, it would surge and die a couple of times. I would have to put it in neutral and rev it up for a bit before I could get it to idle.

IAC? To check it, I remove it, turn the key to the "on" position without starting and check to see if it is moving in and out? Correct? Also, I don't know what the IAC looks like, can someone take a pic? Also, can I just go to NAPA and tell them I need an IAC from a 2000 Chevy 5.7l EFI engine? My boat is a 2000 Maristar 230 VRS with the 330hp LTR engine.

Thanks

h2oski
05-17-2010, 10:00 AM
My 2004 xstar did this when the K&N air filter was moist from washing. Wet actually

JimN
05-17-2010, 10:04 AM
I just picked up a 2000 Prostar 205V with 160 hours at the end of last year...I was only able to take it out twice before storing for the winter, and boat ran great.

I de-winterized and took the boat out, and it had a hard time keeping from stalling, even died twice on me. RPM's were fluctuating between 500 and 1000. Boat ran great above idle, but each time I would bring it back to neutral, it would almost stall, rev up, down, up down, etc...

Maintenance done:

Impeller
Plugs
PCV valve
Cleaned Spark arrestor
Pulled Idle Air Sensor and cleaned
Oil change
Transmission Oil Change
I added Stabil to a full tank at the end of last year.

This is my first MC and I've been learning a ton on this forum. Any ideas what would be causing this?

"Idle Air Sensor"? Where, exactly, is this? There's no such thing. If you're referring to the cylindrical part with four wires attached, that's the Idle Air Control and has no ability to sense anything.

Was it running OK until it warmed up, or did it start bogging as soon as you started it? It it was running OK when it was cold and started to run badly once it warmed up, shut it down, remove the flame arrestor (clean this if you haven't), and look at the throttle plate. If it has no small hole, it may need a firmware update. The first 2000 boats, sold in late 1999, didn't have this hole and Rochester took it upon themselves to delete it after MC and Indmar had done their development and fuel mapping for these boats and motors. It wouldn't have been a problem if they had told someone about it but they didn't and it caused a hot start issue. The fix was to open the IAC a bit more and any MC dealer should be able to do this for you if it's the cause of the problem.

Call MC, tell them your hull ID and motor serial number and ask if it A) needed the firmware update and B) if it was needed, was it done by a dealer?

If this isn't the issue, check the fuel pressure (it should be 30lb+ at KEY ON/engine off, Idle, 2000 RPM and WOT) and take a fuel sample. This is the first thing anyone with an injected motor should do when performance takes a dump. Second, is to check for spark.

JimN
05-17-2010, 10:07 AM
I'm having the same problem. Boat runs flawless when warm. I was trying to teach my wife wakeboarding yesterday. I could go neutral, drive, neutral, drive, no problem, no surging. If I had the boat off for a while then started it, it would surge and die a couple of times. I would have to put it in neutral and rev it up for a bit before I could get it to idle.

IAC? To check it, I remove it, turn the key to the "on" position without starting and check to see if it is moving in and out? Correct? Also, I don't know what the IAC looks like, can someone take a pic? Also, can I just go to NAPA and tell them I need an IAC from a 2000 Chevy 5.7l EFI engine? My boat is a 2000 Maristar 230 VRS with the 330hp LTR engine.

Thanks

DO NOT remove the IAC and turn the key ON. This will cause the pintle to come out and if that happens, it's not going to be in the correct position unless it's reparked manually (using a diagnostic computer). When it's done manually, the ECM will close it, sense a current rise and count the steps to its "home" position. This doesn't happen when it's not in diagnostic mode.

seth25
05-17-2010, 10:11 AM
ok, thanks, do not remove. Can I check it while it is still installed?

JimN
05-17-2010, 10:42 AM
ok, thanks, do not remove. Can I check it while it is still installed?

In the LTR, it's harder to see but it's still possible. The flame arrestor needs to be removed first. Have someone turn the key to on and you should be able to see the tip move. You can also listen for it- if the buzzer makes it impossible when you turn the key ON, listen for a slight buzzing sound after turning it off.

goodelsha
06-07-2010, 01:17 PM
I installed a new IAC and it solved the problem! I picked it up at local autoparts store for $90Thanks for all the input and helping me get this fixed. Boat starts right up and idle's fine now.

MariStar-Man
06-07-2010, 01:42 PM
That's Great! Prop's to Coz, Seth25 and JimN for their detailed and knowledgable input...

seth25
07-13-2010, 01:30 PM
Back to the top....

What did you tell them at the parts store to get the correct part? A 2000 chevy truck with the 5.3 efi engine?

Mine is getting a little annoying. Runs great when started, but I usually have to start it twice. First time starting it surges and dies, second time, it surges, but usuall keeps running after the initial surge.

Thanks
Seth

goodelsha
07-13-2010, 09:34 PM
I took the IAC into CarQuest and they matched it for me.....Part # 73-4333